TP-Link wireless access point repaired. Model: TL-WA501G
A few weeks ago, my family and I moved from one house to another. We were moving our stuff from the old house to our new rented house. I tried to power on this device to get wireless internet in the house, it did not power up.
This device runs on 9 volt power transformer and when I checked it with the voltmeter, it gave me 12 volts reading which an indication of a good working power transformer. The power light was off and seems like the device was completely dead.
The moment I took the cover off, I headed directly to the main fuse and the four diodes on that board. I was not really shocked to see that the one main fuse was open. FB1 was open and FB2 was not.
I could just replace that fuse and try it again but I wanted to know first why the fuse was open. Usually when fuse was open, there is something wrong with the diode bridge rectifier. In my case there were four diodes and when I checked them with the meter, two of them were shorted out.
I replaced the four diodes. Here is a good advice to take into account. When there are two diodes shorted out and the others are not, it is better to replace all of them. I wanted to power up the device but again, I wanted to make sure that everything on that board is working fine. I put a 100 watt light bulb to the main fuse. In this case it was fuse marked FB1 and powered up the device, the power light and the other lights on this device came on indicating a good working internet access point device.
I replaced the FB1 fuse with another one and powered up the device. All was working fine and I could see a good signal on my laptop.
Later on, my wife and I decided to buy a new one. I bought a two in one device; access point and router. So I sold this one and bought the new device.
So, my wife and I were happy and the customer who bought the access point was happy because he bought for a cheap price. Mission accomplished.
This article was prepared for you by Waleed Rishmawi, one of our ‘Master Authors’ and currently working in the Bethlehem area of Palestine repairing electrical and electronic equipment. Please give a support by clicking on the social buttons below. Your feedback on the post is welcome. Please leave it in the comments.
By the way if you have any good repair article that you want me to publish in this blog please do contact me HERE.
(8)Dislikes
(0)
15 Comments
Leave a Reply
Amir Mukhtar
September 8, 2013 at 4:52 am
sir
thanks you for your great sharing knowledge about WiFI Device.
thanks you a lot
yours student
Amir Mukhtar Ashrafi
Waleed Rishmawi
September 9, 2013 at 3:11 pm
Amir: you are most welcome.
Jerry B.Balbin
September 8, 2013 at 8:20 am
Hi,
I just want to ask and your advice. can we use 12v or 24v light bulb instead of using 100w light bulb? because the power of that TP-link is only 12v. And what kind of fuse did you use to replace that smd fuse and what ampere? because in my experience not all smd fuse have marking of ampere. in case of smd fuse that don't have marking of ampere and don't have any diagram to look, what is the best way to replace a defective smd fuse?
Waleed Rishmawi
September 9, 2013 at 3:20 pm
I am not sure if you can use 12 or 24 votls light bulb or not. actually I have not giving it any thought.I will check it out though. very good question my friend.
about the fuse, i just replaced it with the same part from the same device that I have in my shop. I keep a lot of those and use them as parts. I am not sure if there is an formula about finding the rate of the fusre out there. if someone has any information about this please let us know.
sorry I was not much of a help. thanks for the questions. I will look into them.
Gerald Musy
September 12, 2013 at 2:55 pm
Hi Waleed,
I always appreciate your articles covering a wide range of (sometimes unusual) electronic circuits.
Regarding the fuse question, there is no simple answer. Fuses are designed to blow if the current exceeds the rated value. However, they also have a time related characteristic. Some types of fuses can withstand up to 10 times or more the rated value during a short time (slow blow fuses) while others will blow immediately if the current exceeds the rated value (fast blow fuses).
In your circuit there is a rectifier and a capacitor. We can assume that the first time the circuit is powered on there will be a peak of current for a short time until the capacitor is charged. This is what slow blow fuses were designed for and I would recommend this type.
As for the value this is pretty much a guess. In some circuits we would calculate the maximum possible current and size the fuse adding 50% of this value. On your circuit I would measure the current during normal operation (this would be an average) and add at least 100% for the value of the fuse, i.e. if the current is 200 mA I would put a 400 or 500 mA fuse. Then monitor the equipment for a while to make sure that this is OK.
Maybe someone has a more scientific answer?
Cheers,
Gerald
Waleed Rishmawi
September 13, 2013 at 3:30 am
Gerald: thanks for your imput.totaly agree my friend. thanks for sharing
beh
September 8, 2013 at 8:47 am
HI WALEED
like all your past articles also this one is full of useful points . thanks for your efforts .
regards
beh
Waleed Rishmawi
September 9, 2013 at 3:13 pm
Beh: I am really glad your liked my article. that is a motivation for me to keep going. God bless you. thanks for the encouragement.
Waleed Rishmawi
September 9, 2013 at 3:33 pm
Jerry: my amp rate was 0.8 which is less than on ohm. there is formula that I totally forgot about. Amp=Watt/voltage= amp rate. I hope this helps.
Naseem
September 10, 2013 at 6:09 pm
Hi Mr.Walid,
at first thanks for the report.
I think these access points have separate power supply which provide 12vdc, so what is the function of these 4 diodes/bridge rectifier here...?
regards,
Waleed Rishmawi
September 11, 2013 at 3:06 pm
Naseem: you are welcome.
yes, they are but the power adaptor for this device, is 9 vold AC. so these are for changing it into 9 DC volt.
beh
September 11, 2013 at 11:31 pm
waleed
you are unique in the middle east even in the world.
beh
Waleed Rishmawi
September 12, 2013 at 2:33 pm
Thanks Beh. I appreciate it.
Naseem
September 17, 2013 at 6:33 pm
thanks dear walid.
Felippe
December 24, 2015 at 9:23 am
Can i change the fuse with a wire?
thanks!